Technical Field
Embodiments of the present invention relate to a management system, a communication control method, and a communication system.
Background Art
In recent years, communication systems for performing phone conversation or video conference through the communication network such as the Internet or private lines are widely used due to increasing demands for reduction in cost and time. When communication among a plurality of communication terminals is started, such communication systems exchange contents of data such as image data and audio data with each other. Accordingly, the communication among the participants who use the communication terminals is realized. Moreover, as a method of sending contents of data from one communication terminal to some other communication terminals, the publish-subscribe model is known in the art (hereinafter, the publish-subscribe model may be referred to simply as “pub/sub model”).
For example, a method for providing access control in the content-based publish/subscribe system is known in the art (see JP-2007-287148-A). In this method, messages are delivered from publishing clients to subscribing clients via a plurality of routing brokers. In this method, the routing brokers select a starting point where a new access control rule is established. The messages prior to the selected starting point are sent to the subscribing clients only when these messages satisfy a subscription filter and an access filter before a change that is associated with an access control version identifier. Moreover, the messages after the selected starting point are sent to the subscribing clients when these messages satisfy both the subscription filter and the access filter after the change that is associated with the access control version identifier.
According to the publish/subscribe system in JP-2007-287148-A, the rule of access control that a client performs on a message can be changed before and after a starting point where a new access control rule is established. However, with the known communication systems of the publish-subscribe (pub/sub) model, the access to a message cannot be controlled for every service that a client uses.